TOKYO, May 12 (Reuters) - Japan’s JXTG Holdings said on Friday its Caserones copper mine in Chile produced 91,000 tonnes in the fiscal year ended March, missing an earlier target of 98,000 tonnes, due to a power outage in the area and system glitch in February.

The output is less than two-thirds of the 150,000 tonnes of concentrate planned when the company started construction of the mine. Caserones has been plagued by a series of technical problems in its ramp-up stage that have pushed back the timeline for bringing it to full capacity.

JXTG expects Caserones to produce 130,000 tonnes of copper concentrate in the year to next March 31, 140,000-145,000 tonnes in fiscal 2018/19, and 150,000 tonnes in 2019/20, Senior Vice President Yasushi Onoda told Reuters after an earnings conference.

“The problems at the mine have solved quickly and it has been operating at around 90 percent of capacity since March (this year),” a company spokesman said.

Output at the project - 77.37 percent-owned by a joint venture between JXTG and Japan’s Mitsui Mining and Smelting Co Ltd - has been behind schedule since it started producing in May 2014 in the arid mountains of northern Chile. Its troubles highlight the challenges facing miners in Chile now that most of the more accessible deposits have been tapped out.

Caserones booked a recurring loss of 28.4 billion yen ($250 million) in the year ended March 31, but is expected to nearly break even in the current year and aims to generate a profit of over 10 billion yen in fiscal year 2019/20, the spokesman said.

Japanese trading house Mitsui & Co owns the remaining 22.63 percent stake in the mine.